Digalactosyl Diglyceride Research Articles

Manipulation of Galactolipid Fatty Acid Composition with Substituted Pyridazinones

The fatty acid composition of the major lipids of the chloroplast membranes, the mono- and digalactosyl diglycerides, can be definably altered with various substituted pyridazinones. Galactolipid fatty acid composition of wheat (Triticum aestivum L.) can be altered so that there is a decrease in linolenic acid accompanied by an increase in linoleic acid without a shift in the relative proportion of saturated to unsaturated fatty acids; the fatty acid composition can be shifted toward a higher proportion of saturated fatty acids; or the fatty acid composition of the monogalactosyl diglycerides can be altered in preference to the digalactosyl diglycerides. Also, the light-mediated parallel accumulation of chlorophyll and linolenic acid can be separated with a substituted pyridazinone. The substituted pyridazinones may be useful tools in clarifying the role the galactolipids and their component fatty acids play in the structure and function of chloroplast membranes in higher plants.

Dual character of lipid composition of the envelope membrane of spinach chloroplasts

The envelope membrane was isolated from intact spinach chloroplasts by gentle osmotic treatment in a medium containing appropriate amounts of cations to prevent dissociation and fragmentation of the thylakoids. This treatment allowed us to separate effectively the envelope membranes from the thylakoids with one-step (0.6 M/0.9 M) sucrose density gradient centrifugation. The envelope membrane contained both glyceroglycolipids and glycerophospholipids, as does the thylakoid membrane. There were, however, notable differences in the relative amounts of lipid components between these two membranes. The major glyceroglycolipid in the envelope membrane was digalactosyl diglyceride, whereas monogalactosyl diglyceride was the major one in the thylakoid. The envelope membrane was characterized by a high content of glycerophospholipids, as much as three-fold that in the thylakoid membrane. Phosphatidyl choline, which is known to be minor in the thylakoids and abundant in the microsomal and mitochondrial membranes, was a major component, accounting for 50% of the total glycerophospholipids. The dual character of lipid composition of the envelope membrane is discussed in terms of its chemical and structural connection to the other intracellular membrane systems.

Combination and Positional Distribution of Fatty Acids in Plant Digalactosyl Diglycerides

Summary The positional distribution of palmitic acid in digalactosyl diglycerides from 29 plants selected from algae to flowering plants is not as exclusive as in some phospholipids or triglycerides and varies with the taxonomic position of the plant. The tendency was observed that the lower the position in the plant system the higher the proportion of palmitic acid at C-2. In angiosperms substantial amounts of palmitic acid were found at C-2 in those plants, which contain hexadecatrienoic acid in monogalactosyl diglycerides. Fatty acid pairings were investigated in unhydrogenated compounds by gas-liquid chromatography and mass spectrometry. In all vascular plants 18:3/18:3- and 18:3/16:0-combinations are predominant. More impressively than analysis of overall fatty acid composition, analysis by mass spectrometry demonstrates the great differences in the diglyceride parts of monogalactosyl-, digalactosyl- and sulfoquinovosyl diglycerides.

Oxidation of free and esterified linoleic and linolenic acids in bread doughs by wheat and soya lipoxygenases

AbstractLipids containing 14C‐labelled linoleic and linolenic acids were added to flour which was then made into bread doughs with or without 2% enzyme‐active soya flour. The 14C‐labelled lipids and their oxidation products were analysed as intact lipids or as 14C fatty acid methyl esters by thin‐layer chromatography. In the control doughs wheat lipoxygenase oxidised free fatty acids and monoglycerides. In doughs containing soya flour, steryl esters, triglycerides, diglycerides, mono‐galactosyl diglycerides, digalactosyl diglycerides and phosphatidyl choline were also oxidised, and the oxidation of these lipids is attributed to soya lipoxygenase.

Beiträge zur physiologie einheimischer algen 5. Einige aspekte des photosynthetischen C-metabolismus der süßwasserrotalge Audouinella violacea (Kütz) Hamel

Summary Audouinella violacea , a fresh water red alga usually growing epiphytically on Lemanea fluviatilis , accumulates Mannitol as reserve carbohydrate. During photosynthetic carbon fixation serine is rapidly synthetized, comparable to results obtained with other red algae. Monogalactosyl diglyceride, digalactosyl diglyceride, sulfoquinovosyl diglyceride and steryl glycoside were demonstrated to be present in the lipid fraction.

Straight-chain unsaturated fatty acids and cyclopentenyl fatty acids in leaf lipids of Caloncoba echinata and Hydnocarpus anthelminthica

The total lipids in leaves of Caloncoba echinata and Hydnocarpus anthelminthica exhibited consistent fatty acid patterns with palmitic, linoleic and α-linolenic acids being the major acids. Small amounts of cyclopentenyl fatty acids were found in C. echinata (4.4%) and in H. anthelminthica (0.5–1.5%). Analyses of the constituent fatty acids of individual lipid classes showed cyclopentenyl fatty acids to be present mainly in triglycerides and as free fatty acids. The major lipids in the two species were monogalactosyl diglycerides, digalactosyl diglycerides and phosphatidyl cholines. The straight-chain monounsaturated fatty acids consisted mainly of Δ-9 isomers, whereas the polyunsaturated fatty acids belonged exclusively to the Δ-9 series. There was no structural relationship between the straight-chain unsaturated acids and the cyclopentenyl acids.

Galactolipid Synthesis in Vicia faba Leaves

The galactose, glycerol, and fatty acids of mono- and digalactosyl diglycerides (MGDG and DGDG) have been separated and analyzed for (14)C activity after (14)CO(2) feeding of Vicia faba leaf discs. Fully expanded and developing leaves were analyzed at time intervals following feeding during continuous illumination. In addition, fully expanded leaves were analyzed after similar times in complete darkness. In all cases, (14)C was incorporated very rapidly into galactose, whereas glycerol and fatty acids were labeled much more slowly and over a longer period of time. The data are consistent with the galactosylation of a diglyceride to MGDG which is in turn galactosylated to DGDG. The data suggest that the formation of diglycerides suitable for galactosylation to MGDG is slow in comparison to the galactosylation process. It is also suggested that DGDG may be formed from more than one pool of MGDG. The complete analysis of the (14)C incorporation into galactose appears to represent the only satisfactory method of comparing galactolipid synthesis by (14)C incorporation. Estimates of comparative rates of synthesis of MGDG and DGDG have been made on this basis.

Gas-liquid chromatography of plant galactolipids and their deacylation and methanolysis products

The gas-liquid chromatography of monogalactosyl diglyceride (MGDG) and digalactosyl diglyceride (DGDG) and their deacylation and methanolysis products is reported. MGDG and DGDG and their galactosyl monoglycerides were chromatographed as their trimethylsilyl derivatives. Galactosyl monoglycerides were produced by partial deacylation of the diglycerides with Grignard's reagent and pancreatic lipase. The products of complete deacylation, mono- and digalactosyl glycerols, were separated as O-methyl, O-acetyl, O-trimethylsilyl and O-trifluoroacetyl derivatives. Gas-liquid chromatography of derivatives of the methanolysis products of MGDG and DGDG and the methylated galactosyl glycerols allowed the separation and quantitative recovery of the galactose and glycerol of both lipids and the two galactoses of DGDG.

Lipid and sterol composition of the pollen of the west african oilpalm, Elaeis guineensis

The lipid classes, fatty acid methyl esters and the sterols of oilpalm pollen were analysed. The neutral lipid fraction consisted of triglycerides, esterified and free sterols and trace amounts of hydrocarbons. Monogalactosyl and digalactosyl diglycerides, phosphatidyl choline, phosphatidyl inositol and phosphatidyl ethanolamine represented the polar lipids. The major fatty acids were linoleic, palmitic and linolenic acids together with small to trace amounts of oleic, stearic, arachidic, myristic, lauric, palmitoleic and margaric acids. Unsaturated fatty acids predominated over saturated ones in the ratio of 3:2. The 4-desmethyl sterols were the major phytosterols in the free form but they constituted a lower proportion of the sterols in the esterified state. 28-Isofucosterol was isolated and characterized as the principal sterol.

Enzymatic acylation of steryl glycoside

Summary A soluble protein fraction obtained from leaves of Vicia faba catalyzes the acylation of steryl glycoside to acyl steryl glycoside by acyl groups originating from galactolipids. Using semisynthetic alactolipids it was shown that both acyl groups from C-1 and C-2 of mono- and digalactosyl diglyceride are transferred to steryl glycoside. The same protein fraction was also active in the formation of acyl galactosyl diglyceride. Using the same semisynthetic galactolipids as above it was demonstrated by mass spectrometry that during formation of acyl galactosyl diglyceride the acyl groups from the donor molecules are transferred exclusively to the galactose moiety of the accepting monogalactosyl diglyceride, its diglyceride portion remaining unaltered. After working out an assay based on the transfer of tritiated oleoyl groups from digalactosyl diglyceride to steryl glycoside it was shown that most of the soluble activity in leaf homogenates was not localized in chloroplasts.

Lipids in plant tissue cultures IV. The characteristic patterns of lipid classes in callus cultures and suspension cultures

Lipids from callus cultures and suspension cultures of higher plants constitute 5 to 8% of the dry tissue's weight. The predominant lipid classes are the sterols, steryl esters, steryl glycosides and esterified steryl glycosides. Considerable amounts of a variety of sterylglycolipids, whose structures are not completely elucidated, are also present. Triglycerides and phospholipids occur in small proportions, whereas monogalactosyl diglycerides, digalactosyl diglycerides and sulfoquinovosyl diglycerides are present only in traces, if at all. β-Sitosterol is the predominant constituent sterol, stigmasterol and campesterol as well as a variety of as yet unidentified sterols occur in smaller proportions. The major constituent fatty acids are palmitic, oleic, linoleic and linolenic acids. Saturated very long-chain fatty acids are found in smaller proportions. Unusual fatty acids, such as epoxy acids, which occur in the seed lipids of certain plants, are not found in tissue cultures derived from these plants. Clucose and traces of galactose are the only sugars obtained by acid hydrolysis of the glycolipids occurring in plant tissue cultures.

Biosynthesis of digalactosyl diglyceride in Vicia faba leaves

Developing and mature leaf tissue from Vicia faba plants were pulse-fed 14-CO2. The lipids were extracted at intervals after exposure to light, and the galactolipids monogalactosyl diglyceride (MGDG) and digalactosyl diglyceride (DGDG) were separated. After methylation and methanolysis, gas-liquid chromatography was used to separate the two galactose units of DGDG and the galactose of MGDG. The specific activities of the galactoses and the changes over the time period of the experiment were determined. The results support the view that DGDG is formed by galactosylation of MGDG. This does not take place by a rapid two-enzyme system reaction but more slowly in two phases: galactosylation of a pool of newly formed MGDG and a more random galactosylation of MGDG. There is no evidence of a high turnover of galactose in these lipids.

The Lipids in Plant Tissue Cultures Compared to the Lipids of Photosynthetic and Non‐photosynthetic Plants and Plant Organs

AbstractThe pattern of lipid classes in plant tissue cultures is similar to that in non‐photosynthetic plants and plant organs, mono‐galactosyl diglycerides, digalactosyl diglycerides, sulfoquinovosyl diglycerides and phosphatidyl glycerol being very low or absent. In contrast, photosynthetic plants and plant organs contain these classes of compounds in substantial proportions. The lipids in plant tissue cultures as well as in roots of higher plants and root‐like structures of lower plants are rich in steryl glycosides and esterified steryl glycosides.

Phosphoglycerides of Trichophyton terrestre and One Phenotype Selected from the Apollo 16 Microbial Ecology Evaluation Device

Total lipid extracted from wild-type Trichophyton terrestre CDC-X285 was found to be 2.0 percent of the dry cell weight. The total lipid contained the following phospholipid components identified by silicic acid-impregnated thin-layer and paper chromatography: phosphatidyl inositol, phosphatidyl choline, phosphatidyl serine, and phosphatidic acid. The total lipid extracted from the phenotype T. terrestre 7048-1 isolated from the Apollo 16 Microbial Ecology Evaluation Device (MEED) was found to vary according to the time at which the phospholipids were extracted. The Trichophyton phenotype was selected from a cuvette housed in the MEED exposed to specific space parameters including ultraviolet light of known wavelengths and energy levels in deep space. The phospholipid components, identified in the phenotype were phosphatidyl ethanolamine and cardiolipin. The major lipid fraction was composed of digalactosyl diglyceride and monogalactosyl diglyceride. An unusual lipid was detected in the phenotype, which appeared to be sterol glycoside.

Effect of crop maturity on leaf lipids.

AbstractStudies extending throughout a period of 100 days' growth have been made on the total lipids of ryegrass, kale and fodder radish. Expressed in terms of % dry matter, lipids are at a maximum of about 10 to 11% during the period of vegetative growth. Lipid yields in absolute terms are maximal at 200–300 kg/ha after 56 to 70 days from sowing, at which stage lipids have fallen to 7 to 9% of total dry matter, according to species.Considering the fatty acids as a whole, dominant components are linolenic and palmitic, the latter rising and the former falling as maturation progresses. Minor fatty acids show no clear trend. More specific changes in fatty acid profiles are revealed when individual lipid classes are studied separately.Lipid classes display a predictable change in pattern as maturation progresses. New growth is rich in partial glycerides and free sterols, and particularly in mono‐ and digalactosyl diglycerides and sulphoquinovosyl diglyceride. Leaves from mature or senescing crops show progressive falls in these components, accompanied by the appearance of triglycerides, free fatty acids and steryl glycosides. In the case of fodder radish the accumulation of the hydrocarbon, n‐nonacosane, is a noteworthy feature. The principal phospholipids do not change appreciably with maturation.The trends observed on maturation show common general patterns for all the leafy crops so far studied. They do emphasise, however, the crucial importance of specifying both species and duration of growth when quoting data on leaf lipid compositions.

Comparative properties of four galactosyl lipids as antigens in liposomes

Two sphingosyl galactolipids, galactocerebroside and mixed gangliosides, and two glyceryl galactolipids, mono and digalactosyl diglycerides, were compared for immunological activity in liposomal model membranes. The liposomes were prepared with one of several synthetic lecithins or with beef sphingomyelin. Specific complement-dependent glucose release as was found in all cases, although high titer antiserum was not obtained against monogalactosyl diglyceride. With galactocerebroside, the degree of glucose release was inversely related to the phospholipid fatty acid chain length. The relative efficiencies of these substances in terms of antigenic expression and/or immunogenicity was in the order: ganglioside > digalactosyl diglyceride > galactocerebroside > monogalactosyl diglyceride. Reciprocal serological cross-reactivity was observed between ganglioside and galactocerebroside on the one hand and between mono and digalactosyl diglycerides on the other. Cross-reactivity between these two groups occured in four out of six possible combinations studied. Anti-digalactosyl diglyceride was the only anti-serum with an apparent high degree of specificity and it did not cross-react with either cerebroside or ganglioside. Cross-reactivity was influenced by the phospholipid fatty acid chain length, liposomal antigen concentration and the antibody titer against the immunizing antigen.

Some observations on biosynthesis and ratio regulation of mono- and digalactosyl diglycerides by chloroplasts and other subcellular fractions from spinach leaves

Summary Evidence is presented that biosynthesis of galactolipids is influenced by enzymes involved in galactose metabolism. A soluble, heat labile inhibitor of protein nature is present in the 100,000 × g supernatant remaining after centrifugaron of a homogenate of spinach leaves. The ratio of monogalactosyl diglyceride to digalactosyl diglyceride in spinach chloroplasts is affected by freezing and thawing and by Triton X-100. Freezing and thawing of osmotically shocked chloroplasts increases monogalactosyl diglyceride formation, while addition of Triton X-100 results in a relative increase in digalactosyl diglyceride formation. The possibility of transfer of galactolipids between subcellular particles (mitochondria and microsomes) and chloroplasts is discussed.

Permeability and membrane lipid metabolism of Phaseolus vulgaris infected with Uromyces phaseoli II. Changes in lipid concentration and 32P incorporation into phospholipids

Phospholipids and glycolipids of rust-infected leaf halves and uninfected halves of the same leaves were quantitatively determined and compared with the lipids of healthy primary leaves of bean plants. The phosphatidyl-choline, phosphatidyl-ethanolamine, phosphatidylinositol and sulphoquinovosyl diglyceride (SL) content of the infected halves was the same as in the control plants. The infected tissue showed a decrease in monogalactosyl diglyceride (MGG), digalactosyl diglyceride (DGG) and phosphatidyl-glycerol (PG) and an increase in phosphatidyl-serine (PS) and phosphatidic acid content. These differences were localized mainly in the region of the pustule and not in the surrounding mycelium-free tissue. The amount of all phospholipids and glycolipids in the uninfected leaf halves was slightly lower than in the controls. The ungerminated and germinated uredospores of the parasite contained no MGG, DGG, SL or PG. The infected half leaves showed an increase in 32P incorporation into all phospholipids especially into PS. The differences in 32P-incorporation between the phospholipids of the uninfected half leaves and the controls were only small. These results were discussed in relation to permeability changes of rust-infected bean tissue.

カボチャのグリセロ糖脂質

1. Monogalactosyl diglyceride (MGD), digalactosyl diglyceride (DGD), trigalactosyl diglyceride (TGD) and sulfoquinovosyl diglyceride (SQD) were found to be present in pumpkin. MGD, DGD and TGD were isolated and purified. 2. Main fatty acids of glyceroglycolipids isolated were linoleic and linolenic acid, and major sugar component was galactose. 3. Fundamental structure of TGD in pumpkin was presumed to be 1, 2-diacyl-3-O-[α-D-galactopyranosyl-(1'→6')-O-α-D-galactopyranosyl-(1'→6')-O-β-D-galactopyranosyl]-sn-glycerol.

Permeability and membrane lipid metabolism of Phaseolus vulgaris infected with Uromyces phaseoli III. Changes in relative concentration of lipid bound fatty acids and phospholipase activity

Fatty acids from membrane lipids and phospholipase activity of rust-infected half leaves and uninfected halves of the same leaves were determined and compared with healthy primary leaves. The following lipids were analysed for their fatty acid composition: monogalactosyl diglyceride (MGG), digalactosyl diglyceride (DGG), phosphatidyl-choline (PCH), phosphatidyl-ethanolamine (PE) and phosphatidyl-glycerol (PG). The major fatty acids detected in these lipids of both bean leaves and fungal uredospores were palmitic, stearic, oleic, linoleic, linolenic and in PG, trans-three-hexadecanoic acid. The PE and PCH isolated from the infected half leaves contained a higher amount of unsaturated fatty acids than the corresponding lipids from the two other tissues. The PE and PCH from fungal uredospores showed a higher degree of unsaturation than the lipids from bean leaves. The changes in fatty acid composition of PG, MGG and DGG were small and possibly not significant. The differences in fatty acid composition were localized mainly in the region of the pustule. The adjacent fungus free host tissue was affected only to a small extent. The infected tissue showed an increase in phospholipase activity as compared with the controls and the uninfected leaf halves. The results were discussed mainly in relation to permeability changes of rust-infected bean tissue.